Typewriting machine



Nov. 7, 1939. w, DOBSQN 2,178,681

TYPEWRITING MACHINE Filed May 28, 1956 &

Fig.5. 2/

ATTO R N EY- Patented Nov. 7, 1939 UNITED STATES PATENT OFFICETYPEWRITING MACHINE Application May 28,

4 Claims.

This invention relates to stop-devices, employed in mechanisms, forarresting and limiting the movements or strokes of certain parts, and isconcerned particularly with the class of mechanism, as, for example, atypewriter, adding machine or the like, in which reduction of impactnoises of parts against stops and accurate limitation of the movementsor strokes of the parts by the stops are important requisites as, forinstance, in typewriter case-shift mechanisms.

Certain stop-devices heretofore used include noise-reducing cushioningmeans such as leather, felt, rubber, cork, or the like, or metalsprings, and such cushioning means being yielding and soft do not standup or wear well, and thus make it difiicult to maintain the requisiteaccuracy of movement or stroke to which the parts must be limited by thestop-devices.

For precise limitation of movements or strokes of the parts, theconventional solid metal abutments are effective, and have beenheretofore used but at the cost of much and objectionable noise ofimpact.

Moreover, the manufacturing cost of abutments having cushioning devices,such as leather, felt, and the like, compares unfavorably with the costof the conventional solid abutments.

It is therefore an object of my invention to provide an inexpensivestop-abutment or device capable of arresting and limiting the stroke ofa part with the degree and permanence of accuracy obtainable with theconventionable solid metal abutment, and with a degree ofimpactnoise-reducing utility comparable with or better than thatobtained with the conventionally cushioned abutment.

To this end, I obtain a good result by constructing an abutment of hardmaterial, preferably metal, and sectioning, stratifying, or laminatingit, preferably so that the arrested or impacting part strikes onedivision or section transversely, and the struck section is supported byan underlying division or section.

I have found, in addition to splitting or dividing the abutment orimpact-resisting device, that spot-welding the split or originallyseparate sections, constitutes an inexpensive way of securing thesections together, and conduces to the noisereducing utility of theabutment.

I have found further that by making the outer or impact-receivingportion of the abutment in the form of a thin metal disk or wafer andspotwelding it, facewise, only at its marginal portion to a companionface of an underlying body, the interior or unwelded. section of thedisk or 1936, Serial No. 82,175

wafer, may become, by using a hollow or annular welding die, slightlycrowned, and therefore slightly separated from the underlying body-faceby an interstice, and that the interstice also conduces to thenoise-reducing utility of the device.

Thus I gain, and preferably by the latter construction, an abutment thatwill arrest and limit the movement of the stroke of a mechanism-partwith the same good maintenance of precision as obtains with theconventional solid metal abutment and with a degree of impact-noisereduction comparablefavorably with or better than that obtainable withsay a leather-faced abutmerit.

Good results may also be obtained by other forms of localizedspot-Welding, as, for example, by spot-welding only at the center oronly at one side of the impact-receiving disk or wafer.

It will be understod that the arrangement of impact-noise-reducing partsand the dimensional proportion thereof, herein illustrated by way ofexample, may be varied Without departing from the principles of theinvention.

Thus, one principle of the invention is to laminate, stratify orsectionalize the hard or metallic device that is disposed at or near thepoint of impact for absorbing the impact and its noise, to the end thatone or each section neutralizes or silences the sonorous vibrations ofanother section.

Another principle, conducive to sonorousvibration-silencing, and tostructural unification, is to unite the laminae, strata or sections atspots, so as to leave them non-adhesive at other spots; and this isexemplified and accomplished most economically by localized spot-weldingof the sections or laminae.

Another principle resides in forming, in the *train or pile of metallicor hard-material parts or sections that serve to take up the impact,such interstice or slight localized separation of sections or laminae aswill be conducive to silencing the sonorous vibrations induced by theimpact.

Other features and advantages will hereinafter appear.

In the accompanying drawing,

Figure 1 is a side view showing separately the parts of one form of thedevice, namely, a caseshift stop for a typewriter, and comprising therelatively thin disk or wafer and the underlying body.

.Figure 2 is a cross-section view of the spotwelding dies or electrodesand represents the abutment-parts therein being spot-welded only at theouter margin of the disk or anvil, and

further represents the inner section of the disk as becoming slightlycrowned at the welding operation.

Figure 3 is a plan View of the impact-receiving end of the finishedabutment.

Figure 4 is a cross-section view of a typewriter and representsprovision of the novel device therein for accurately limiting and at thesame time quietly arresting the case-shift movements or strokes of theplaten-frame.

Figure 5 is a side view of the abutment.

The invention is illustrated in connection with a typewriter, andcase-shift structure therefor, of the kind seen in my Patent No.2,030,056, dated February 11, 1936.

In said typewriter, main frame It] mounts a rock-shaft H, havingside-arms l2 pivotally connected at l3 to a case-shiftable frame M,.inwhich travels a carriage l5 having a platen IS; the carriage and framel4 having guide-rails I]. Said rock-shaft H and its side-arms l2co-operate with anti-friction guides l8 to guide the frame 24 incase-shift movements or strokes effected by operating a key-lever l9.Said caseshift movements are limited by means of upper and lowerabutments orstop-screws 2i, threaded in lugs 22 of the typewriter-frameE0 to respectively face upper and lower faces of a stop-end 23 of theside-arm 52.

For accurately limiting the case-shift movements and reducing the noiseof impact of the stop-end 23 of the arm !2 against either stopscrew 2!,the latter may be constructed as follows. A butt or body 25 of metal,which may be steel, having a head 26 and a shank 21, threadable into thetypewriter-frame lug 22, is originally separate, see Figure 1, from arelatively thin head-capping disk or wafer 28, which may also be ofsteel. Saidwafer or veneer 28 may be of substantially the same diameterand outline as the body-head 26, the latter being shown as of hexagonalcross-section to take a case-shift-adjusting wrench.

The body 25 and the capping disk 23 are welded together in a suitableelectrical spot-welding apparatus. For this purpose, said weldingapparatus has a lower electrode or die 29 provided with a counterbore orrecess 30 forming a seat 3! for the body-head 26, and the sides of saidcounterbore 30 serving to locate the disk 28 and head 28 in appropriatealignment as seen in Figure 2. v

Said lower die has a bore or pit 33 for clearing the body-shank, andthrough which pit an ejector (not shown) may be worked.

An upper electrode or die 3 of the welding apparatus is designed topress only upon a portion, preferably the marginal portion of the disk28, and for this purpose the disk-pressing face 35 of said upper die 34is made annular as by drilling the end of the upper die to form a space36 and a disk-engaging annulus 3?.

With the body 25 and capping disk 28 in place in the lower die 29 andthe annular upper die 34 pressed down upon the disk 28, thereby forcingparticularly the marginal portion of the disk 28 down upon the head 26,the application of an electric welding current from a suitable source 38causes the disk 28 and body 25 to become welded together only at themarginal portion of the disk, as indicated by the annular weld or spots39, Figures 2 and 3.

Substantially the entire under side of the capping disk 253 may beoriginally in contact with the entire top surface of the body-head 26,so that,

under the welding operation, the disk tends and is permitted to warp orbuckle upward within the upper die-space 35 to form the central orinterior section of the disk 28 into a slight crown 40, therebyseparating the under side of said central disk-section from contact withthe top surface of the head 25, and forming the interstice 4|, Figure 2.

The adhesion between the disk 28 and head 26 formed by the annular weldmay be circumferentially uniform as represented at Figure 2. Or theadhesion formed by the weld may vary or be interrupted in spots asdiagrammatically represented in Figure 3, wherein the outlines 42represent individual areas of adhesion, and which areas togetherconstitute the annular weld 39 at the margin of the disk 28.

Given a head 26 and a disk or wafer 28, having a diameter of say of aninch across the hexagon flats, a suitable thickness for the disk 28would be, say, twelve thousandths of an inch. With these proportions thecenter section of the disk would buckle upward to make the separation orinterstice 4!, between the head 26 and disk 28, say two thousandths tofive thousandths of an inch at the center.

The impacting part, namely, the stop-end 23 of the side-arm l2, may beformed to have its point of impact upon the section or disk 28 mainlyabove the interstice 4! or unwelded portion of said disk, and, for thispurpose, said stop-end 23 may strike primarily upon the top of the crown40.

The impact-resisting device, abutment or stopscrew 2i being constructedentirely of hard material or metal and in compact, sectional, laminatedor Stratified, that is, sonorous-vibration-suppressing, form, avails tolimit the caseshifts with enduring precision, and to effect notablereduction or practical elimination of the impact noise usually obtainingwith the conventional solid-metal stop-device; and it will be understoodthat the same benefits may be had, by use of the invention, in othermechanisms having stop-limited movable parts.

M represents a check-nut for securing the stopscrew 2 I in adjustedposition.

Variations may be resorted to within the scope of the invention, andportions of the improvements may be used without others.

Having thus described my invention, I claim:

1. A typewriter or the like having two relatively moving parts impactingone against the other for limiting the relative movement, one of saidparts including, in order to quietly arrest and precisely limit saidrelative movement, a metal body, and a metal veneer thereon to impactagainst the other part in arresting said relative movement, thecontiguous surfaces of said metal body and metal veneer being coheredtogether locally, so as to leave a portion of said contiguous surfacesunattached, whereby sonorous vibration induced at the impact of saidparts is suppressed and the impact noise substantially reduced.

2. A typewriter or the like having two relatively moving parts impactingone against the other for limiting the relative movement, one of saidparts including, in order to quietly arrest and precisely limit saidrelative movement, a metal body, and a metal veneer thereon to impactagainst the other part in arresting said relative movement, thecontiguous surfaces of said metal body and metal veneer being coheredtogether locally, so as to leave a portion of said contiguous surfacesunattached, whereby sonorous vibration induced at the impact of saidparts is suppressed and the impact noise substantially reduced, theunattached portion of the contiguous surfaces being arranged to form aninterstice therebetween to conduce the suppression of the sonorousvibration.

3. A typewriter or the like having two relatively moving parts impactingone against the other for limiting the relative movement, one of saidparts including, in order to quietly arrest and pre cisely limit saidrelative movement, a metal butt, and a metal veneer on an end surface ofsaid butt to impact against the other part in arresting said relativemovement, the contiguous surfaces of said metal butt and metal veneerbeing cohered together and only at the margin so as to leave a portionincluding the inner or central part of said contiguous surfacesunattached, whereby scnorous vibration induced at the impact of saidparts is suppressed and the impact noise substantially reduced.

4. A typewriter or the like having two relatively moving parts impactingone against the other for limiting the relative movement, one of saidparts including, in order to quietly arrest and precisely limit saidrelative movement, a metal butt, and a metal veneer on an end surface ofsaid butt to impact against the other part in arresting said relativemovement, the contiguous surfaces of said metal butt and metal veneerbeing cohered together and only at the margin so as to leave a portionincluding the inner or central part of said contiguous surfacesunattached, whereby sonorous vibration induced at the impact of saidparts is suppressed and the impact noise substantially reduced, saidbutt and metal veneer being relatively arranged so as to form aninterstice at said unattached central part, to conduce to suppression ofthe sonorous vibration.

WILLIAM A. DOBSON.

